9 + 12 = 12 + 9 a.
Commutative Property of Multiplication
b.
Commutative Property of Addition
c.
Associative Property of Multiplication
d.
Associative Property of Addition

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.